In a wireless communication system, a receiver needs to generate an estimate corresponding to a signal received from a transmitter prior to decoding. Along with the signal estimate, additional parameters that affect the decoding based on the estimate also need to be computed. Typically, these parameters are used to soft/hard decode the estimates and are sometimes referred to as slicing parameters.
Various aspects of the signal processing are generally done in the physical layer of the receiver using fixed point arithmetic. In fixed point arithmetic, each of the quantities are represented using a finite number of bits. When a quantity becomes so large/small that it cannot be reliably represented using the allocated number of bits an overflow/underflow occurs, respectively. Each of the finite arithmetic signal processing implementations should ensure that overflows and underflows never, or very rarely, occur.
When a receiver desires to generate estimates corresponding to signals received from multiple transmitters concurrently, the received power levels corresponding to signals received from different transmitters may, at times, be substantially different. In addition, as the number of transmit antennas from which signals are being received increases the number of multiplications and number of divisions increases in the processing which increases the likelihood of an overflow or underflow condition.
Based on the above, there is a need for methods and apparatus to avoid overflow or underflow from occurring while generating estimates corresponding to received signals from one or more transmitters. It would be beneficial if at least some of these methods and apparatus were flexible and/or facilitated efficient symbol estimation while reducing or eliminating processing overflows or underflows when there are different received power levels and/or when different numbers of transmit antennas are used.